Response surface modeling and optimization of nitrate removal from aqueous solutions using magnetic multi-walled carbon nanotubes

Modeling of the Contact Removal of Iron From Groundwater

“…Such a film is regarded as charged and the process of iron removal from the water after the oxidation block takes place as inside of the filter. During filtering compounds of oxidized iron adhere to the surface of the granules with its simultaneous oxidation, that is, the so-called contact iron removal takes place (see [2], [3], [4]). In order to create a mathematical model for describing the physico-chemical processes of removal of iron from water a spatially one-dimensional process of water treatment based on filtration in a polystyrene layer with thickness L (identified with the segment [0, L] along the axis) is considered.…”

“…There are a wide variety of factors affecting the physical and chemical composition of such water: contact time with different rocks and soils, depth of the media, dissociation in aquifers, contact with the atmosphere and surface waters, etc. For most cases the main problem of groundwater is the high content of iron, hydrogen sulfide and free carbon dioxide (see [1], [2], [3], [4], [6], [7]). In our time there are a wide variety of water treatment methods, which can be grouped as follows: reagent-free; reagent; cation exchange; biochemical (see [3], [4], [5], [6], [12]).…”

“…This method can be used if the iron content is up to 10 mg / dm 3 and the pH is above 7 (see [5]). Contact iron removal is provided by filtration of water with high pH and alkalinity and involves the supply of aeration water immediately to the filters without its preliminary retention (see [1], [2], [3], [4], [7]). The process of iron removal can be carried out with the help of a filter of any design with different granular media -gravel, crushed stone, quartz sand, anthracite, granular plastics, foam polystyrene, etc.…”

Adsorption of Nitrate onto ZnCl2‐Modified Coconut Granular Activated Carbon: Kinetics, Characteristics, and Adsorption Dynamics

“…In addition, studies showed the nitrate adsorption due to the different mechanisms [26][27][28][29][30]. e mechanism of nitrate adsorption by magnetic amine-cross-linked biopolymer includes electrostatic attraction, ion exchange, and surface complex formation [27].…”

“…Nitrate was adsorbed by modified biochar (amine-cross-linked reaction that amine group played the main role in nitrate uptake) depending on the electrostatic attraction mechanism [28,30]. In addition, nitrate was adsorbed by magnetic multiwalled carbon nanotubes depending on the magnetic reaction to the desired separation [26].…”